Biology subjects

Fan, L.

Publications and source records attributed to Fan, L..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

Unified Multi-Cohort Harmonisation and Normative Modelling of Neuroimaging Data via Hierarchical GAMLSS

Large-scale neuroimaging studies increasingly pool data across multiple cohorts, scanners, and acquisition protocols, introducing technical between-cohort variation that must be addressed before meaningful biological inference can be drawn. Existing harmonisation methods, particularly ComBat-based approaches, have been widely adopted for this purpose. However, they remain limited by Gaussian assumptions and by their focus on location or location-scale correction. In this study, we propose a unified hierarchical Generalised Additive Models for Location, Scale and Shape (GAMLSS) framework for multi-cohort harmonisation and normative modelling of structural neuroimaging data. The framework models cohort effects directly within all fitted distributional parameters, accommodates any parametric family for which exact inverse mapping is available, and returns harmonised values on the original measurement scale through centile-based quantile mapping. Normative deviation scores are obtained as a direct by-product of the same fitted model, enabling harmonisation and normative inference to be conducted jointly. The method was evaluated in a pooled longitudinal dataset comprising 88,126 observations across 237 structural neuroimaging features from six cohorts spanning childhood to late life: ABCD, IMAGEN, NCANDA, LIFE, UK Biobank, and MAS. Harmonisation performance was compared with ComBat, ComBat-GAM, and ComBat-LS using complementary criteria assessing data retention, residual batch effects, preservation of age-related and sex-related biological signal, and coherence of post-harmonisation lifespan trajectories. GAMLSS achieved near-complete removal of residual cohort effects, retained almost all valid observations post-harmonisation, and showed the strongest overall preservation of biological signal across validation metrics. In particular, it better preserved biologically plausible age trajectories for distributionally complex features such as white matter hypointensity volume, while simultaneously providing harmonised native-scale values and normative deviation scores within a single framework. These findings suggest that hierarchical GAMLSS offers a flexible and practical alternative to existing ComBat-based methods for large-scale neuroimaging harmonisation, particularly for features with non-Gaussian residual distributions and settings where cohort effects extend beyond differences in mean and variance.

neuroscience↗

bioRxiv2026

Epigenetic activation of CHST2 by promoter hypomethylation promotes progression of triple-negative breast cancer

Epigenetic dysregulation is a hallmark of triple-negative breast cancer (TNBC), yet the oncogenic relevance of specific epigenetically activated genes remains poorly defined. In this study, we demonstrate that carbohydrate sulfotransferase 2 (CHST2) is aberrantly upregulated in TNBC across multiple transcriptomic analyses as a consequence of promoter hypomethylation. Elevated CHST2 expression is associated with aggressive clinicopathological characteristics and has been linked to unfavorable patient outcomes in independent cohorts. Functional analyses reveal that CHST2 primarily promotes TNBC cell migration and invasion, while genetic silencing of CHST2 markedly attenuates these malignant phenotypes. Importantly, mutational disruption of CHST2 catalytic activity abolishes its pro-migratory effects, indicating that sulfotransferase activity is essential for CHST2-driven invasiveness. Mechanistically, promoter hypomethylation is experimentally supported as a driver of CHST2 transcriptional activation, linking epigenetic deregulation to enhanced tumor aggressiveness. In addition, tumors with high CHST2 expression exhibit distinct immune-related transcriptional features within the tumor microenvironment. Collectively, these findings identify CHST2 as an epigenetically activated driver of invasive behavior in TNBC and highlight its potential value as a biomarker and therapeutic target for aggressive disease.

cancer biology↗

bioRxiv2026

cGAS-mediated IFN-I signaling contributes to disease progression in drug-refractory epilepsy

Epilepsy is a prevalent neurological disease with a third of patients becoming non-responsive to antiepileptic drugs and developing drug-refractory epilepsy (DRE). Here we report that DRE disease progression is contributed by overactive cyclic GMP-AMP synthase (cGAS), a double-stranded DNA sensor that induces type I interferon (IFN-I) signaling. In human DRE microglia, we observe a robust IFN-I signature and the activation of upstream cGAS-STING signaling. Further, in mouse models of Dravet syndrome, a genetic form of DRE, we observe the activation of the cGAS pathway. We show that microglial cGAS can be activated by DNA released from hyperexcitable neurons. Genetic reduction and pharmacological inhibition of cGAS reduces epileptic phenotypes, glial inflammatory signatures, and neuronal transcriptomic changes, underscoring the therapeutic potential of targeting cGAS for DRE treatment.

neuroscience↗

bioRxiv2026

Identification a Compact Promoter using a New Promoter Selection Strategy and Engineering Hybrid Pol II/III Enable Efficient Genome Editing in Human Retinal Ganglion Cells

Promoters and vectors are critical components of gene therapy, enabling the delivery and expression of therapeutic genes to correct both loss- and gain-of-function mutations. Adeno-associated virus (AAV) vectors are the leading platform for in vivo gene delivery; however, the widely used Streptococcus pyogenes Cas9 (SpCas9, 4.1 kb) approaches the AAV packaging limit of 4.7 kb. This constraint often necessitates dual-vector systems, which reduce therapeutic efficiency, or the use of smaller nucleases such as SaCas9 (3.2 kb) and AacCas12b (3.4 kb), which have lower PAM site frequencies. To enhance promoter selection for gene therapy applications, we developed a strategy to identify compact, cell-preferred RNA polymerase II (Pol II) promoters. Analysis of approximately 300 compact Pol II promoters revealed that exogenous expression levels in one cell type correlate more strongly with those in other cell types than with endogenous expression, underscoring the importance of exogenous expression efficiency in promoter selection. Using this approach, we identified a compact Pol II promoter #2 (Pro2, 133 bp) that drives robust transgene expression in human retinal ganglion cells (RGCs). To enable single-AAV delivery of SpCas9, we analyzed three commonly used Pol III promoters (H1, 7SK and U6) and determined their minimal functional lengths using a CRISPR/Cas9 reporter assay. We further engineered three compact hybrid Pol II/III promoters which combined pro2 with minimal H1, 7SK and U6 (276, 294, and 323 bp) capable of co-expressing SpCas9 and gRNA, enabling efficient genome editing in both transfected HEK293 cells (approaching 100%) and human RGCs (up to 55.9%) from human stem cell-derived retinal ganglion cells (RGCs). Together, these findings establish a framework for developing single-AAV CRISPR-based gene therapy strategies. Authors contributionsPWZ and DJZ conceived the study, designed the experiments, performed data analysis and interpretation, and were the primary contributors to manuscript writing. STZ played a key role in data collection and correlation analysis. YYC, SL, LF, CJK, YD, CAB, JC, and DW contributed to the execution of essential experiments and subsequent data analysis. All authors have read and approved the final manuscript. Declaration of interestsThe authors declare no conflicts of interest.

molecular biology↗

bioRxiv2026

When CycloneSEQ meets Oxford Nanopore Technologies: a performance comparison of contemporary nanopore DNA sequencing platforms

Nanopore sequencing enables direct analysis of native DNA modifications, but these modifications can also introduce systematic basecalling errors. Here, we investigated how bacterial DNA methylation contributes to nanopore substitution errors using matched native whole-genome sequencing (WGS) and methylation-depleted whole-genome amplification (WGA) datasets from six bacterial species across CycloneSEQ (CS) and Oxford Nanopore Technologies platforms (ONT). Adenine-to-guanine (A2G) and guanine-to-adenine (G2A) substitutions were consistently enriched across species, nanopore platforms, sequencing configurations, and basecalling models, indicating a shared nanopore-associated substitution bias. This enrichment remained detectable in WGA reads, whereas native WGS reads showed a further increase. Using independent PacBio methylation profiling, we found that the WGS-associated substitution excess was strongly concentrated around bacterial methylation motifs and was minimal in non-motif regions. The magnitude and substitution pattern of these errors varied among motifs and sequencing platforms. At a subset of motif-associated positions, alternative-base fractions exceeded 50%, producing SNP-like signals. In ONT data, 28 WGS-specific calls survived the applied SNP-calling filters, all within PacBio-supported methylation contexts, and most showed significant strand imbalance. Together, these results identify a shared A2G/G2A substitution bias in all nanopore datasets and support a methylation-associated increase in these errors near bacterial methylation motifs, with some loci producing SNP-like artifacts.

bioinformatics↗

bioRxiv2026

Soluble DLK1 secreted by telomere-shortening-induced senescent microglia impairs oligodendrocyte functions and alters neuronal activity

Aging is the major risk factor for neurodegenerative disease, yet the mechanisms linking physiological aging to brain dysfunction remain unclear. Because telomere erosion is a hallmark of aging, we examined its impact on glial and neuronal physiology. Telomere shortened mice showed lipofuscinosis, hypomyelination, microglial atrophy, and cognitive deficits. Single nuclei RNA-seq revealed accelerated glial aging, elevated microglial senescence pathways, and impaired oligodendrocyte functions. Inducing senescence in human iPSC derived microglia with shortened telomeres identified soluble DLK1 as a novel senescence associated ligand. sDLK1 was increased in the cerebrospinal fluid of telomere shortened and naturally aged mice, and this increase was eliminated by microglial depletion. AAV delivery of sDLK1 in vivo caused hypomyelination and blocked oligodendrocyte lineage progression, demonstrating the detrimental nature of excessive sDLK1. In human iPSC systems, sDLK1 impaired oligodendrocyte maturation and altered calcium signaling in excitatory neurons. These findings identify microglial senescence as a core consequence of telomere shortening and reveal sDLK1 as a microglia-derived senescence ligand that drives oligodendrocyte and neuronal dysfunction in aging.

neuroscience↗

bioRxiv2026

Transplantation of Human IPSC-derived Microglia Ameliorates Neuropathology and Circuit Dysfunction in Progranulin-Deficient Mice

Frontotemporal dementia (FTD) is a major cause of early-onset neurodegeneration characterized by progressive behavioral, emotional, and cognitive decline. Progranulin haploinsufficiency, a leading genetic cause of familial FTD, disrupts lysosomal function, lipid metabolism, autophagy, and neuroimmune signaling across multiple cell types. Increasing evidence indicates that microglia are particularly sensitive to progranulin loss, exhibiting elevated complement activation that contributes to TDP-43 proteinopathy and neuronal dysfunction. Here, we investigate the biological role of restoring progranulin exclusively within microglia by transplanting human induced pluripotent stem cell-derived microglia (iMG) into progranulin (Grn)-deficient mice. We find that wild-type, but not Grn-deficient, human iMG restore brain-wide progranulin levels, normalize microglial transcriptional states, and ameliorate pathological, functional, and behavioral phenotypes associated with progranulin loss. Because microglia are the only source of progranulin in this system, these findings demonstrate that microglial progranulin is sufficient to restore key aspects of cellular, circuit, and behavioral homeostasis in a progranulin-deficient FTD model. More broadly, this work highlights a central, microglia-intrinsic role for progranulin in maintaining brain function and provides a framework for dissecting microglia-specific mechanisms across FTD and related neurodegenerative disorders. One Sentence SummaryOur study demonstrates that xenotransplantation of wild-type human iPSC-derived microglia into progranulin-deficient mice mitigates core neuropathological, network-level, and behavioral features of Frontotemporal Dementia.

neuroscience↗

bioRxiv2025

Pulmonary mRNA-LNP Vaccines for Rapid and Durable Protection Against Bacterial Infection

Pulmonary bacterial infections remain a major clinical challenge. Although vaccination reduces infection rates and mortality, the vulnerable post-vaccination immunity gap can still result in infection and vaccine failure. In addition, effective vaccines are unavailable for many clinically important bacterial pathogens. Here, we report a pulmonary mRNA-lipid nanoparticle (mRNA-LNP) vaccine incorporating a novel ionizable lipid engineered for localized high-level expression, which elicits both rapid and durable protections against bacterial lung infections, effectively bridging this critical window of vulnerability. Intratracheal delivery of mRNA-LNP rapidly primes lung neutrophils and macrophages into a transcriptionally pre-activated state, enhancing their phagocytic activity and enabling rapid, antigen-independent bacterial clearance during the early post-vaccination period (approximately 1-7 days). Subsequently, vaccination induces potent antigen-specific adaptive responses, conferring sustained protection against both laboratory and clinical drug-resistant Pseudomonas aeruginosa strains. Single-cell transcriptomics and immune profiling reveal coordinated activation of innate and adaptive immune programs. This dual-phase immune response exemplifies a paradigm-shifting vaccine design that integrates innate and adaptive immunity to confer both immediate and long-term protection. Our findings establish a mechanistic basis for rapid antibacterial defense and highlight pulmonary mRNA-LNP vaccination as a promising strategy for combating respiratory infections.

bioengineering↗

bioRxiv2025

STING_IFN_CH25H lipid axis links innate immune activation to tau pathology

Genetic risk for Alzheimers disease is strongly enriched in pathways governing microglial activation and cholesterol metabolism, yet how these processes converge to drive neurodegeneration remains unclear. Here, we identify the oxysterol 25-hydroxycholesterol (25- HC) as a pathogenic lipid downstream of the cGAS-STING-IFN pathway. In models of tau pathology, interferon signaling induces Cholesterol 25-hydroxylase (CH25H) expression in microglia. Ch25h deletion in female P301S mice suppressed tau aggregation, preserved synapses, prevented brain atrophy, and rescued memory. Mechanistically, loss of CH25H disrupted STING trafficking, attenuated IFN activation, dampened self-perpetuating microglial inflammation. Strikingly, 25-HC directly accelerated tau propagation in human iPSC derived neurons. It also disrupted lysosomal and mitochondrial lipid composition, driving cholesteryl ester accumulation and promoting apoptosis under tau-induced stress. These findings define a STING-IFN-CH25H lipid axis that bridges innate immune activation to tau pathology and toxicity, offering a tractable therapeutic pathway for inflammation-driven neurodegenerative conditions.

neuroscience↗

bioRxiv2025

Cross-Species Cortical Geometry Reveals Conserved Gradients Across Primates and Human-Specific Expansion

The primate cerebral cortex, characterized by its complex structural geometry, underlies advanced cognitive functions and represents a defining feature distinguishing primates from other mammals. However, cross-species patterns of cortical geometry and the links between human cortical geometry and transcriptional architecture remain poorly understood. We developed a geometry-based cross-species cortical alignment framework to systematically investigate the similarities and differences in structural connectivity and cortical expansion characteristics among macaques, chimpanzees, and humans, and additionally explored the transcriptional underpinnings of human cortical geometry. Our analysis revealed conserved spatial patterns of cortical geometric features across species, providing the foundation for constructing a cross-species structural common space to support the alignment framework. We found that primary sensory, somatomotor, and face-selective regions exhibited high structural connectivity similarity across species, whereas prefrontal and parietal association cortices displayed significant divergence. We also identified disproportionate cortical expansion in the default mode network, with a consistent expansion trend across different evolutionary lineages in primates. Furthermore, neuroimage-transcription analysis indicated that cortical geometric features were correlated with transcriptional profiles enriched in neurodevelopmental and connectivity-related pathways. These results highlight a conserved yet hierarchically differentiated organization of the cerebral cortex in primates, providing new insights into the biological basis of human brain evolution.

neuroscience↗

bioRxiv2025

Metabolomic analysis of Chinese chestnut (Castanea mollissima Bl.) leaves in response to Oligonychus ununguis feeding stress

Piercing-sucking insects such as the chestnut red mite (CRM; Oligonychus ununguis) damage leaves by extracting mesophyll cell nutrients, thereby reducing photosynthesis and nut yield in Chinese chestnut (Castanea mollissima Blume). However, the metabolic basis of the chestnut response to mite stress remains elusive. To address this, leaf metabolomics was conducted on four varieties with different resistance levels. Resistance grades were determined by the leaf chlorosis index, and three comparison groups were established. Secondary metabolome profiling revealed that resistant varieties showed greater metabolic changes under infestation than susceptible ones. In total, 713 total metabolites and 275 metabolites with significantly differential accumulation among germplasms were identified across the comparisons. KEGG enrichment highlighted 246 metabolites and 75 differential metabolites involved in flavonoid, flavonol, and phenylpropanoid biosynthesis. Notably, 27 phenylpropanoids and flavonoids accumulated significantly in resistant varieties but were largely absent or unchanged in susceptible ones. These findings suggest that specialized phenylpropanoids and flavonoids, along with their associated pathways, play key roles in CRM resistance, providing a foundation for breeding mite-resistant chestnut varieties.

plant biology↗

bioRxiv2025

Panax notoginseng saponins protect the blood brain barrier against oxidative stress by activating the Akap12/PI3K/AKT/AQP1 signaling axis

Oxidative stress is a key pathological factor that contributes to blood-brain barrier (BBB) disruption during ischemic injury. Panax notoginseng saponins (PNS), the primary bioactive components of Panax notoginseng, possess potent antioxidative and vasoprotective activities. This study aimed to elucidate the molecular mechanisms by which PNS regulate endothelial integrity and BBB permeability under oxidative stress conditions. Mouse brain microvascular endothelial cells (bEnd.3) were treated with hydrogen peroxide to induce oxidative damage, followed by intervention with PNS. Transcriptomic and proteomic analyses revealed that Akap12 (A-kinase anchoring protein 12) and Aquaporin 1 (AQP1) were key molecules involved in PNS-mediated endothelial protection. H2O2 exposure markedly suppressed Akap12 expression and inhibited the PI3K/AKT signaling pathway, leading to elevated AQP1 expression and increased BBB permeability. PNS treatment reversed these effects by restoring Akap12 expression, reactivating PI3K/AKT signaling, and reducing AQP1 levels. Functional validation further showed that AQP1 dysregulation altered the expression balance of tight junction proteins, including Claudin-5 and ZO-1, thereby impairing barrier function. Collectively, these findings demonstrate that PNS protect endothelial cells from oxidative injury by activating Akap12-dependent PI3K/AKT signaling and modulating AQP1-associated tight junction remodeling. This study provides new mechanistic insights into the molecular basis of PNS-mediated BBB protection and suggests potential therapeutic targets for oxidative or ischemic cerebrovascular diseases.

pharmacology and toxicology↗

bioRxiv2025

Identification and functional characterization of an AMD associated c-ABL binding SNP streak within the ARMS2 gene promoter region

BackgroundLarge-scale genome-wide association studies (GWAS) have identified the human 10q26 locus as a major genetic risk factor for age-related macular degeneration (AMD). The AMD-associated interval has been refined to a 5,196 bp segment flanking the ARMS2-HTRA1 region, excluding HTRA1 and the ARMS2 3' indel (443del54ins) variant by risk haplotype analysis. Although the missense SNP rs10490924 has been proposed as a functional variant, its role in AMD remains controversial, and the causative variants and underlying mechanisms within this region remain unresolved. MethodsAn unbiased bioinformatic screen identified a 5-SNP block within the 5,196 bp interval that potentially alters c-ABL protein binding. Protein-DNA interactions were validated using electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays. Genetic association with AMD (dry and wet subtypes) was assessed in patient cohorts using blood genomic DNA. The regulatory effect of the 5-SNP block was further examined using luciferase reporter assays. FindingsWe identified a 5-SNP block located [~]556 bp upstream of the ARMS2 start codon, representing a cluster of predicted c-ABL tyrosine kinase binding sites. This block, in complete linkage disequilibrium with rs10490924 (A69S), showed a strong association with both wet and dry AMD (136 controls, 179 dry AMD, 251 wet AMD). EMSA and ChIP confirmed direct c-ABL binding, while luciferase reporter assays demonstrated reduced transcriptional activity mediated by the 5-SNP block in the presence of c-ABL. InterpretationOur results suggest that the c-ABL-responsive 5-SNP regulatory streak in the ARMS2 promoter region act as functional non-coding elements that may contribute to AMD pathogenesis through altered transcriptional regulation.

molecular biology↗

bioRxiv2025

Intrinsically Disordered Protein Coating for Oral Delivery of Peptide Drugs

AbstractAdvancing oral delivery of peptide therapeutics requires innovative materials that overcome gastrointestinal barriers. We introduce the first engineered synthetic intrinsically disordered protein (SynIDP) that self-assembles into an enteric coating, encapsulating peptide drugs to enhance gastric acid resistance and intestinal targeting. This SynIDP recapitulates the molecular design principles and phase transitions of native IDPs to exhibit temperature-controlled condensation and pH-controlled solidification--both transitions being reversible and precisely tuned to intestinal cues. Through detailed analysis of the kinetics of the liquid-to-solid phase transition, we achieve control over the nano-to-microscale morphology of the protein coating, optimizing drug encapsulation and protection. The coating protects peptide-based weight loss drugs for over 60 minutes in simulated gastric conditions, then dissolves to release the active compound. Oral delivery to obese mice results in more consistent weight loss compared to the unencapsulated drug. This modular protein-based coating is a promising platform technology for enhancing oral peptide drug delivery and improving patient compliance.

bioengineering↗

bioRxiv2025

Membrane protein condensates polymerize actin and form filopodia

Neuronal morphogenesis is guided by filopodia, dynamically generated plasma membrane protrusions filled with parallel actin filaments. However, how filopodial actin filaments are locally produced, organized, and maintained remains unclear. The transmembrane protein PLPPR3 induces filopodia in neurons and other cells. We find that the intracellular domain (ICD) of PLPPR3 forms liquid condensates, which exhibit strong co-partitioning of actin monomers. These condensates promote actin polymerization within the condensates at the expense of actin monomers in the environment, consistent with thermodynamic coupling of actin partitioning and polymerization, which we recapitulate in a modified polymerization kinetics model. This mechanism requires favorable actin partitioning into the condensate relative to the environment. Using crosslinking mass spectrometry, we identify a WH2-like actin-affinity domain within the PLPPR3 ICD. Deleting this domain lowers actin partitioning in vitro and decreases filopodia formation in vivo. Our findings establish a previously unrecognized mechanism for actin network remodeling, in which condensates act as actin sinks, locally boosting monomer concentrations and facilitating polymerization of actin filaments. One sentence summaryOur study uncovers PLPPR3 condensates to locally enrich actin monomers and promote actin polymerization, driving actin network remodeling and neuronal filopodia formation.

cell biology↗

bioRxiv2025

De Novo Design of Anti-Aging Peptides

Aging, a universal biological process in complex organisms, is increasingly recognized to be driven by progressive loss of epigenetic information, as proposed in the Information Theory of Aging (ITOA). However, research on anti-aging peptides remains scarce, with most existing efforts confined to derivatives of natural proteins, while systematic design attempts are virtually absent. This limitation not only restricts discovery within the evolutionary sequence space but also hampers the identification of candidates with novel mechanisms and improved efficacy. Here, we present ElixirSeeker2, the first computational framework for de novo design of anti-aging peptides. By integrating modeling of known anti-aging peptides, activity scoring from the IC50 database, and penalty constraints from toxic peptides, ElixirSeeker2 enables large-scale virtual screening and identification of novel peptide candidates. Several lead peptides demonstrated significant effects in delaying cellular senescence, restoring cellular functions in vitro and in enhancing locomotor activity of aged Caenorhabditis elegans. This study not only validates the feasibility of de novo design in anti-aging interventions but also establishes a strategy for the development of next-generation biologics.

bioinformatics↗

bioRxiv2025

PRIME: A Multi-Agent Environment for Orchestrating Dynamic Computational Workflows in Protein Engineering

Artificial intelligence (AI) is revolutionizing protein engineering, yet its practical application is often hindered by a fragmented toolchain and the specialized expertise required to orchestrate complex computational workflows. To address these challenges, we have developed PRIME, an autonomous protein engineering multi-agent system. The core innovation of PRIME is dynamic workflow synthesis: it interprets high-level engineering objectives, reasons over a curated library of more than 65 validated protein tools, and autonomously constructs custom computational pathways. Crucially, by grounding every step in verifiable tool execution, PRIME mitigates the risk of model hallucination. It also automates the complete pipeline for developing specialized AI models, from data acquisition through training. In a benchmark of 213 multi-step protein engineering tasks, PRIME exhibited superior performance, successfully completing the majority of tasks where state-of-the-art, general-purpose AI agents fail. We validated its capabilities in demanding real-world applications, including the fully autonomous training of a machine learning classifier and the de novo design of a therapeutic antibody against SARS-CoV-2. By abstracting technical complexity, PRIME empowers scientists to execute sophisticated computational experiments with unprecedented flexibility, establishing a new paradigm for autonomous scientific discovery. The PRIME agent and source code will be made publicly available.

bioinformatics↗

bioRxiv2025

Post-inhibitory rebound firing drives hypothalamic activation for male mating

Many behaviorally relevant limbic circuits are dominated by inhibitory connections, raising the question of how neuronal activation arises in such contexts. In male mating, both activation of mPOA and its inhibitory inputs are essential--a paradox previously ascribed to disinhibition. Here, we show that the mPOA largely lacks local inhibitory circuits, arguing against disinhibition. Instead, in vivo recordings reveal that mount-active mPOA neurons are suppressed prior to behavioral onset, and this inhibition negatively correlates with subsequent activation, consistent with post- inhibitory rebound firing (PIR). A biologically plausible conductance-based model demonstrates that synaptic inhibition interacts with T-type Ca{superscript 2} currents -- the ionic basis of PIR -- to promote mPOA neuron firing. Experimentally, bidirectional manipulations of mPOA T-type Ca{superscript 2} channels confirm this mechanism: knockdown reduces PIR and impairs male mating, while overexpression enhances mating. Together, these results identify PIR as a critical mechanism by which inhibition promotes activation in limbic circuits to drive male mating.

neuroscience↗